class Solution:
    def reverseString(self, s) :
        """
        Do not return anything, modify s in-place instead.
        """
        i = 0
        j = len(s)-1
        while(i<j):
            temp = s[i]
            s[i] = s[j]
            s[j] = temp
            i = i+1
            j = j-1
        return s

if __name__ == '__main__':
    S = Solution()
    arr = ["H","a","n","n","a","h"]
    arr = S.reverseString(arr)
    print(arr)